From 52a0936fbc642d102e20ab9c1558d02f7f0ee674 Mon Sep 17 00:00:00 2001
From: Eric Helgeson <erichelgeson@gmail.com>
Date: Fri, 24 Jun 2022 13:39:43 -0500
Subject: [PATCH] Fix onReadCapacity calculation

---
 src/BlueSCSI.cpp | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/BlueSCSI.cpp b/src/BlueSCSI.cpp
index c731bf6..f2d17f8 100644
--- a/src/BlueSCSI.cpp
+++ b/src/BlueSCSI.cpp
@@ -999,16 +999,18 @@ byte onRequestSense(SCSI_DEVICE *dev, const byte *cdb)
  * READ CAPACITY command processing.
  */
 byte onReadCapacity(SCSI_DEVICE *dev, const byte *cdb)
-{  
+{
+  uint32_t blocksize = dev->m_blocksize;
+  uint32_t blockcount = dev->m_fileSize / blocksize - 1; // Points to last LBA
   uint8_t buf[8] = {
-    dev->m_blockcount >> 24,
-    dev->m_blockcount >> 16,
-    dev->m_blockcount >> 8,
-    dev->m_blockcount - 1, // Points to last LBA
-    dev->m_blocksize >> 24,
-    dev->m_blocksize >> 16,
-    dev->m_blocksize >> 8,
-    dev->m_blocksize    
+    blockcount >> 24,
+    blockcount >> 16,
+    blockcount >> 8,
+    blockcount,
+    blocksize >> 24,
+    blocksize >> 16,
+    blocksize >> 8,
+    blocksize
   };
   writeDataPhase(8, buf);
   return SCSI_STATUS_GOOD;